util.js

/**
 * --------------------------------------------------------------------------
 * Bootstrap (v4.0.0): util.js
 * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
 * --------------------------------------------------------------------------
 */
var Util = function ($) {
  /**
   * ------------------------------------------------------------------------
   * Private TransitionEnd Helpers
   * ------------------------------------------------------------------------
   */
  var transition = false;
  var MAX_UID = 1000000; // Shoutout AngusCroll (https://goo.gl/pxwQGp)

  function toType(obj) {
    return {}.toString.call(obj).match(/\s([a-z]+)/i)[1].toLowerCase();
  }

  function getSpecialTransitionEndEvent() {
    return {
      bindType: transition.end,
      delegateType: transition.end,
      handle: function handle(event) {
        if ($(event.target).is(this)) {
          return event.handleObj.handler.apply(this, arguments); // eslint-disable-line prefer-rest-params
        }

        return undefined; // eslint-disable-line no-undefined
      }
    };
  }

  function transitionEndTest() {
    if (typeof window !== 'undefined' && window.QUnit) {
      return false;
    }

    return {
      end: 'transitionend'
    };
  }

  function transitionEndEmulator(duration) {
    var _this = this;

    var called = false;
    $(this).one(Util.TRANSITION_END, function () {
      called = true;
    });
    setTimeout(function () {
      if (!called) {
        Util.triggerTransitionEnd(_this);
      }
    }, duration);
    return this;
  }

  function setTransitionEndSupport() {
    transition = transitionEndTest();
    $.fn.emulateTransitionEnd = transitionEndEmulator;

    if (Util.supportsTransitionEnd()) {
      $.event.special[Util.TRANSITION_END] = getSpecialTransitionEndEvent();
    }
  }
  /**
   * --------------------------------------------------------------------------
   * Public Util Api
   * --------------------------------------------------------------------------